Saturday, September 21, 2013

New paper finds another amplification mechanism by which the Sun controls climate

A paper published today in Advances in Space Research finds small changes in solar wind speed may affect both the North Atlantic Oscillation [NAO] and the Arctic Oscillation [AO] on both short-term [day-to-day] and long-term [inter-annual] timescales. Both the NAO and AO in turn have major effects upon global climate. The authors propose these effects are related to "A connection via the global atmospheric electric circuit and cloud microphysical changes" [similar but not the same as the cloud seeding hypothesis of Svensmark et al]. The paper may demonstrate yet another amplification mechanism by which tiny changes in solar activity can be amplified to produce large effects upon climate.

Fig. 2. Superposed epoch analyses of daily values of NAO (a) and (d), AO (b) and (e) and the SWS [solar wind speed] itself in km/s (c) and (f), with the key days being minima in the SWS in winters (Nov.–March). The low-volcanic eras (1967-1983, 1985-1993 and 1995-2011) are on the left (a)–(c) and the high volcanic eras (Nov. 1963-March 1966, Nov. 1983-March 1985, Nov.1993-Mar. 1995) are on the right (d)-(f). The solid lines are the mean of parameters of all the events and the dashed lines are the error of the mean value.

Abstract

Indices of the North Atlantic Oscillation and the Arctic Oscillation show correlations on the day-to-day timescale with the solar wind speed (SWS). Minima in the indices were found on days of SWS minima during years of high stratospheric aerosol loading. The spatial distribution of surface pressure changes during 1963-2011 with day-to-day changes in SWS shows a pattern resembling the NAO. Such a pattern was noted for year-to-year variations by Boberg and Lundstedt (2002), who compared NAO variations with the geo-effective solar wind electric field (the monthly average SWS multiplied by the average southward component, i.e., negative Bz component, of the interplanetary magnetic field). The spatial distribution of the correlations of geopotential height changes in the troposphere and stratosphere with the SWS; the geoeffective electric field (SWS∗Bz); and the solar 10.7 cm flux suggests that solar wind inputs connected to the troposphere via the global electric circuit, together with solar ultraviolet irradiance acting on the stratosphere, affect regional atmospheric dynamics.

UV only affects stratospheric temperatures (and thus regional atmospheric dynamics) by interacting directly with ozone on the way through.

I submit that the ozone chemistry effect is enough on its own to produce observed climate changes.

http://www.newclimatemodel.com/new-climate-model/

Of course other aspects of solar behaviour including the strength of the solar winds change at the same time but I am not aware of any mechanism whereby changes in such other variables can contribute to the observed climate consequences of solar variability.

The effect of more cosmic rays whilst plausible would not result in changes in stratospheric temperatures above the tropopause so the Svensmark hypothesis has difficulties.